Golf is a game which requires exacting techniques to achieve a proper swing. One aspect of a proper swing relates to the swing plane which is the plane in which club should substantially move during a swing. The basic determinative factors with regard to the position of a golfer's swing plane is his or her physical stature and his or her address posture. The more a golfer bends over the ball from the waist at address, and the closer he sets his hands to his body, the more upright becomes the plane in which he naturally tends to swing. Conversely, short golfers tend to swing in a flatter plane, i.e. a less upright plane, than tall golfers because their lack of height in relation to the standard length of club shafts forces them to stand farther from the ball. The swing plane also shifts between different clubs because of differences in their relative lengths. For example, a 9 iron is shorter than a 5 iron thereby causing the golfer to swing the 9 iron in a more upright plane than the 5 iron.
Another important aspect of a proper golf swing is the desirability that the head of the club strike the ball at that point of the golf swing where the club head velocity is the greatest and that such speed by maintained into the follow-through. Maximum force of impact between the club face and the ball is obtained without club head torquing when the ball is hit in the "sweet spot" of the club head face. The sweet spot is typically located at the center of the club face and has been thought of as the location on the club face directly forward of the center of gravity of the club head. For example, a golfer may locate the sweet spot of a putter by holding it lightly between the thumb and forefinger at the top end of the grip and then gently tap the face of the putter head with an object such as a ball at different locations on the club face until the club head recoils straight back and forth like a pendulum without twisting or torquing off-line. This approach does locate the sweet spot of the club while essentially at rest. However, as the club is fully swung, often in various swing planes due to swing inconsistencies of golfers of average ability, the sweet spot actually shifts due to redistribution of the mass of the club head with respect to the swing plane where it extends through the club head, and to differences in different speeds of different portions of the club head. Because the sweet spot of a club in motion is determined relative to mass and velocity of the club, it may be referred to as the center of inertia of the golf club. Such shifting of the center of inertia hampers a golfer's ability to make ball contact at the sweet spot. The further a ball is hit from the center of inertia the more it will tend to be misdirected or imparted with a side spin.
It thus is seen that a need remains for a golf club that can substantially maintain its center of inertia or sweet spot in the same location upon the club head regardless of the orientation of the plane in which the club is swung or its velocity. It is to the provision of such therefore that the present invention is primarily directed.